AMSOIL Signature Series Synthetic Motor Oil delivered outstanding engine protection following more than 100,000 miles of severe service in a Las Vegas taxi, while Signature Series Synthetic Automatic Transmission Fluid virtually eliminated harmful sludge and wear in another's taxi's transmission following more than 180,000 miles.

In a dynamometer test designed to simulate conditions even more extreme than the demanding stop-and-go driving conditions of a motorcycle rally or parade route, AMSOIL 20W-50 Synthetic Motorcycle Oil demonstrated outstanding performance in temperatures more than 500°F.

Compares the performance in laboratory tests and cost-effectiveness of AMSOIL Signature Series Synthetic
Motor Oil to several passenger-car/light-truck synthetic motor oils widely considered by marketers and consumers to be the best available.

AMSOIL 75W-90 Long Life Synthetic Gear Lube provided excellent differential protection following more than 500,000 miles
of severe service, with gears and bearings earning perfect merit ratings of 10 in multiple categories.

The AMSOIL Performance Test Archive documents the consistent high performance of AMSOIL synthetic lubricants throughout the company’s history. Click the link above to review samples of past performance tests and technical studies.